Multicylinder block for air cooled engines and method of forming the same



June 5 1933- c. 5. BROWN 5 19 MULTICYLINDER BLOCK FOR AIR COOLED ENGINES AND METHOD OF FORMING THE SAME Fil ed Dec. 17, 1931 ATTORN EEYS.

Patented June 20, 1933 UNITED STATES PATENT FFECE CHARLES S. BROWN, OF SYRACUSE, NEW YORK MULTIGYLINDER BLOCK FOR AIR- GOOLEd) ENGINES AND METHOD OF FORMING THE SAME Application filed December 17, 1931. Serial No. 581,650.

This invention relates to internal combustion engines and particularly cylinders for air cooled internal combustion engines, and has for its object a cylinder block for air f5] cooled engines which is particularly slmple and economical in construction and a method of forming the same.

The invention consists in the novel features and in the combinations and construc- '10, tions hereinafter set forth and claimed.

In describing this invention reference is had to the accompanying drawing in which like characters designate corresponding parts in all the views.

Figure 1 is a plan View, partly broken away, of a cylinder block embodying th1s invention. 7

Figure 2 is a side elevation of parts seen in Figure 1.

Figure 3 is an enlarged fragmentary elevation on line 2+2, Figure 1.

Figure 4 is a fragmentary plan view similar to Figure 1 of another form of my cylinder block.

Since there is greater distortion in air cooled cylinders than in water cooled cylinders due to more uneven distribution of heat, it heretofore has been thought necessary to cast and machine each air cooled cylinder separately and therefore, the cost of production of a multi-cylinder air cooled engine is greater than enbloc water cooled engines.

The principal object of this invention is a multi-cylinder block for air cooled engines which can be cast and machined with the same economy as a block water cooled engine and yet have all the advantages of an air cooled engine in which the cylinders are independent of each other.

This multi-cylinder air cooled engine block comprises a base slab 1, a plurality of cylinders 2 on the base and integral therewith having horizontal heat radiating flanges 3 extending lengthwise of the block around and between the cylinders and being connected together or continuous after the casting operation. After the block has been machined, the cylinders are separated, or partially separated, by sets of slots 4, 5, extending in- 50 wardly respectively from opposite sides of the block through the flanges andbetween the cylinders and terminating short of the edges of the flanges at the opposite sides of the block leaving comparatively narrow necks as at 6 of the flanges connecting the flanges. The slots 4, 5, are cut to permit independent action of the cylinders under variations in temperature, as in air cooled engines where the cylinders are formed separately; and are alternately arranged to compensate for relative displacement.

The cylinder block here illustrated is formed of two groups of cylinders 7 and 8, there being two cylinders in each group and the groups are spaced apart a greater distance than the cylinders of either group 7 or 8 and there is a pair of alternately arranged slots 4, 5, between the groups.

The heat radiating flanges are rectangular in plan as distinguished from annular, and as the heat radiating flanges of adjacent cylinders are integral, the cylinder block is rectangular in plan and the slots 4, 5, extend inwardly from opposite longitudinal sides of the block through the flanges.

The method of forming the cylinder block consists in casting the block with the cylinders 2 integral with the base 1 and the flanges 3 connected, machining the cylinders, and then after the cylinders are machined, sawingthe slots 4, 5.

In Figure 4, the block is shown asformed with slots 11 extending. through the flanges between the cylinders and terminating short of the opposite side edges of the flanges or block and with short slots 12 extending inwardly from opposite sides of the block on opposite sides of the end portions of the slots 11. The slots 12 extend, but part way, into the cylinder flangest The slots 11 are usually cored out, and formed during the casting operation, and the short slots 12 by sawing after the block has been machined.

The machining operations consist primarily in boring out and honing the cylinders, and in facing the head ends of the cylinder for receiving the heads, not shown. Also, in boring and tapping holes for receiving studs, screws or bolts to attach the heads of the cylinders.

Owing to this construction of cylinder block,'the cylinders can be held rigid as a unit during the machining operations and hence, the machining operations can be performed as economically as in the blocks of water cooled engines, and afterwards the cylinders separated by the slots 4, 5, or 12, so that they can react independentlyof each other under temperature variations.

In the types of slotting shown in Figure 4:, and between the pairs of cylinders in Figure 1, is shown a flexible zig-zag connection by which the cylinders are held in sideways alinement, but are allowed to expand or contract in the plane of their centers.

What I claim is: c

1. A cylinder block for air cooled internal combustion engines comprising a base, a plurality of cylinders mounted on the base, the block having heat radiating flanges extending along the sides and ends and around the cylinders, the outline of the flanges being rectangular in plan whereby the block is rectangular in plan, the block having slots extending inwardly through the flanges from each longitudinal side of the block between the cylinders. g I y 2. A cylinder block for air cooled. internal combustion engines comprising a base, a plurality of cylinders mounted on the base, the block having heat radiating flanges extending along the sides and ends and around the cylinders, the block having slots extending inwardly through the flanges from each side of the block between the cylinders,said slots extending between the cylinders and ending transversely of the flanges between the cylinders and terminating near and short of the side edges of the flanges and the block and additional slots extending inwardly from opposite sides of the block on opposite sides of the end portions of the former slot-s.

In testimony whereof, I have hereunto signed my name at Syracuse, in the county of Onondaga and State of New York, this 15th day of December, 1931.

CHARLES S. BROWN.

near and short of the edges of the'flanges on the opposite side of the block, and the slots extending inwardly from one side alternating with those extending inwardly from the other side.

3'. A multi-cylinder block for air cooled internal combustion engines comprising a base, a plurality of cylinders mounted on the base and integral therewith and horizontal heat radiating flanges extending lengthwise of the block and around and between the cylinders, the block being provided with sets of slots extending inwardly from each side of the block between the cylinders and terminating short of the edges of the flanges on the other side of the block, the slots of one set alternating with'those of the other.

4. A cylinder block for air cooled engines comprising a base, a plurality of cylinders mounted on the base and integral therewith and horizontal heat radiating flanges extending lengthwise of the block around and between the cylinders, said cylinders being arranged in groups and the groups being separated a greater distance than the cylinders of each group, slots extending through the flanges from each side of the block and between the cylinders and terminating short of the edges of the flanges in the opposite side CWO 

